Method and apparatus for improving a new carrier type in a wireless communication system

ABSTRACT

Methods and apparatuses are disclosed to improve a new carrier type in a wireless communication system. The method includes having, in at least one subframe, more than one number of available resource elements among Physical Resource Blocks (PRBs) in a cell. The method further includes receiving an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same number of available resource elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/755,150 filed on Jan. 22, 2013, the entiredisclosure of which is incorporated herein by reference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to methods and apparatuses for improving a newcarrier type in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure for which standardization is currentlytaking place is an Evolved Universal Terrestrial Radio Access Network(E-UTRAN). The E-UTRAN system can provide high data throughput in orderto realize the above-noted voice over IP and multimedia services. TheE-UTRAN system's standardization work is currently being performed bythe 3GPP standards organization. Accordingly, changes to the currentbody of 3GPP standard are currently being submitted and considered toevolve and finalize the 3GPP standard.

SUMMARY

Methods and apparatuses are disclosed to improve a new carrier type in awireless communication system. One method includes having, in at leastone subframe, more than one number of available resource elements amongPhysical Resource Block (PRB) pairs in a cell. The method furtherincludes receiving an Enhanced Physical Downlink Control Channel(ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the samenumber of available resource elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A orLTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra MobileBroadband), WiMax, or some other modulation techniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support one or more standards such asthe standard offered by a consortium named “3rd Generation PartnershipProject” referred to herein as 3GPP, including Document Nos. R1-124776,“On New Carrier Type”, RP-121415, “New WI proposal: New Carrier Type forLTE”, TS 36.211 V11.1.0, “E-UTRA Physical channels and modulation”, TS36.213 V11.1.0, “E-UTRA Physical layer procedures”, R1-124717, “Oncollision between DM RS and PSS/SSS in new carrier”. The standards anddocuments listed above are hereby expressly incorporated by reference intheir entirety.

FIG. 1 shows a multiple access wireless communication system accordingto one embodiment of the invention. An access network 100 (AN) includesmultiple antenna groups, one including 104 and 106, another including108 and 110, and an additional including 112 and 114. In FIG. 1, onlytwo antennas are shown for each antenna group, however, more or fewerantennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112and 114 transmit information to access terminal 116 over forward link120 and receive information from access terminal 116 over reverse link118. Access terminal (AT) 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal(AT) 122 over forward link 126 and receive information from accessterminal (AT) 122 over reverse link 124. In a FDD system, communicationlinks 118, 120, 124 and 126 may use different frequency forcommunication. For example, forward link 120 may use a differentfrequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access network transmitting through a single antenna to all itsaccess terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, aneNB, or some other terminology. An access terminal (AT) may also becalled user equipment (UE), a wireless communication device, terminal,access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmittersystem 210 (also known as the access network) and a receiver system 250(also known as access terminal (AT) or user equipment (UE)) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain embodiments, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

Turning to FIG. 3, this figure shows an alternative simplifiedfunctional block diagram of a communication device according to oneembodiment of the invention. As shown in FIG. 3, the communicationdevice 300 in a wireless communication system can be utilized forrealizing the UEs (or ATs) 116 and 122 in FIG. 1, and the wirelesscommunications system is preferably the LTE system. The communicationdevice 300 may include an input device 302, an output device 304, acontrol circuit 306, a central processing unit (CPU) 308, a memory 310,a program code 312, and a transceiver 314. The control circuit 306executes the program code 312 in the memory 310 through the CPU 308,thereby controlling an operation of the communications device 300. Thecommunications device 300 can receive signals input by a user throughthe input device 302, such as a keyboard or keypad, and can outputimages and sounds through the output device 304, such as a monitor orspeakers. The transceiver 314 is used to receive and transmit wirelesssignals, delivering received signals to the control circuit 306, andoutputting signals generated by the control circuit 306 wirelessly.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the invention. In thisembodiment, the program code 312 includes an application layer 400, aLayer 3 portion 402, and a Layer 2 portion 404, and is coupled to aLayer 1 portion 406. The Layer 3 portion 402 generally performs radioresource control. The Layer 2 portion 404 generally performs linkcontrol. The Layer 1 portion 406 generally performs physicalconnections.

For LTE or LTE-A systems, the Layer 2 portion may include a Radio LinkControl (RLC) layer and a Medium Access Control (MAC) layer. The Layer 3portion may include a Radio Resource Control (RRC) layer.

In 3GPP R1-124776, a new carrier type was introduced to reduce thesignalling overhead and to increase spatial efficiency such thatinterference is reduced and energy cost is efficient. In 3GPP RP-121415describes the new carrier type as follows:

In a first phase specify the New Carrier Type (NCT) being aggregatedwith a legacy LTE carrier.

-   -   Specify necessary enhancements for transmission of data and        control as well as the necessary UE mobility support on the New        Carrier Type.    -   Evaluate the benefits achievable from the standalone New Carrier        Type over those achieved from legacy LTE and from the carrier        aggregated New Carrier Type    -   Identify the scenarios for the standalone New Carrier Type        In a second phase specify enhancements to the New Carrier Type        also considering the findings of the small cell related Rel-12        studies (from RAN#61)    -   If justified by the evaluation, specify necessary means to allow        standalone and macro-assisted operation on the New Carrier Type,        including        -   A broadcast mechanism to acquire system information, a            common search space for ePDCCH and UE mobility support.        -   If justified by the small cell related studies, specify            necessary means to support a dual dormant/active state,            which means DTX like eNB behaviour (with long DTX cycles)            and corresponding UE procedures, with or without reduced CRS            in the active state. Note that the dual dormant/active state            can be specified for NCT aggregated with a legacy carrier            and/or operating in a macro assisted mode even if the            standalone carrier is not justified by the evaluation.    -   Verify the suitability of the solutions specified in the first        phase for the purposes of standalone New Carrier Type operations        and small cells and update the necessary functionalities and        signals if necessary.    -   Specify corresponding UE and eNB core requirements        Note that the work will proceed from the starting point of the        agreements and working assumptions reached so far in RAN1 during        the Rel-11 work item.    -   Note that small cell related enhancements will include also        non-NCT related solutions, which will be specified in other WIs.

In the above-discussed 3GPP documents, there were discussions about howmany legacy signals can be removed from the New Carrier Type (NCT). Asdisclosed in 3GPP TS 36.211 V11.1.0, a signal such as PrimarySynchronization Signal (PSS)/Secondary Synchronization Signal (SSS) isneeded to guarantee the synchronization performance at least for thestand-alone case. In an unsynchronized, non-standalone case, the impactto the overhead reduction seems neutral as PSS/SSS is transmitted every5 ms. As a result, 3GPP RAN1 concludes that it is possible to keepPSS/SSS transmission on the NCT.

In 3GPP TS 36.211 V11.1.0, it is assumed that the density ofCell-specific Reference Signal (CRS) will be reduced both in time domainand frequency domain as CRS accounts for a significant part ofsignalling overhead. Therefore, some of the transmission schemedisclosed in Rel-10 cannot be supported as their demodulation is basedon CRS. Instead, the Demodulation Reference Signal (DMRS) introduced inRel-10 will be considered as the basic demodulation reference. Onepotential issue of this design is DMRS and PSS/SSS could collide. InRel-10, this issue is acknowledged and the proposed solution providesthat those physical resource blocks (PRBs) containing PSS/SSS orPhysical Broadcast Channel (PBCH) could be scheduled with for legacytransmission scheme (based on CRS). In such a situation, the userequipment (UE) would assume that there is no transmission based on DMRS(as disclosed in 3GPP TS 36.213 V11.1.0), which is not possible giventhat the CRS would be eliminated.

3GPP discloses that for a type 1 frame structure:

-   -   the UE is not expected to receive PDSCH resource blocks        transmitted on antenna port 5 in any subframe in which the        number of OFDM symbols for PDCCH with normal CP is equal to        four;        -   the UE is not expected to receive PDSCH resource blocks            transmitted on antenna port 5, 7, 8, 9, 10, 11, 12, 13 or 14            in the two PRBs to which a pair of VRBs is mapped if either            one of the two PRBs overlaps in frequency with a            transmission of either PBCH or primary or secondary            synchronisation signals in the same subframe;    -   the UE is not expected to receive PDSCH resource blocks        transmitted on antenna port 7 for which distributed VRB resource        allocation is assigned.    -   The UE may skip decoding the transport block(s) if it does not        receive all assigned PDSCH resource blocks. If the UE skips        decoding, the physical layer indicates to higher layer that the        transport block(s) are not successfully decoded.

3GPP discloses that for a type 2 frame structure:

-   -   the UE is not expected to receive PDSCH resource blocks        transmitted on antenna port 5 in any subframe in which the        number of OFDM symbols for PDCCH with normal CP is equal to        four;    -   the UE is not expected to receive PDSCH resource blocks        transmitted on antenna port 5 in the two PRBs to which a pair of        VRBs is mapped if either one of the two PRBs overlaps in        frequency with a transmission of PBCH in the same subframe;    -   the UE is not expected to receive PDSCH resource blocks        transmitted on antenna port 7, 8, 9, 10, 11, 12, 13 or 14 in the        two PRBs to which a pair of VRBs is mapped if either one of the        two PRBs overlaps in frequency with a transmission of primary or        secondary synchronisation signals in the same subframe;    -   with normal CP configuration, the UE is not expected to receive        PDSCH on antenna port 5 for which distributed VRB resource        allocation is assigned in the special subframe with        configuration #1 or #6;    -   the UE is not expected to receive PDSCH on antenna port 7 for        which distributed VRB resource allocation is assigned;    -   with normal cyclic prefix, the UE is not expected to receive        PDSCH resource blocks transmitted on antenna port 5 in DwPTS        when the UE is configured with special subframe configuration 9.    -   The UE may skip decoding the transport block(s) if it does not        receive all assigned PDSCH resource blocks. If the UE skips        decoding, the physical layer indicates to higher layer that the        transport block(s) are not successfully decoded.

A UE is not expected to monitor an enhanced physical downlink controlchannel (EPDCCH) candidate, if an enhanced control channel element(ECCE) corresponding to that EPDCCH candidate is mapped to a physicalresource block (PRB) pair that overlaps in frequency with a transmissionof either Physical Broadcast Channel (PBCH) or primary or secondarysynchronization signals in the same subframe.

Accordingly, in 3GPP R1-124717, RAN1 began considering severalalternatives that were raised during Rel-11 discussions as follows:

-   -   Alt 1: Avoid collisions between PSS/SSS and DM-RS by moving the        PSS/SS        -   1a: keeping Rel-8 relative locations of PSS/SSS        -   1b: change relative locations of PSS/SSS    -   Alt 2: Change the DM-RS pattern on NCT (i.e. in all subframes)        to give better performance for PDSCH demodulation in the absence        of a legacy control region (and thereby also avoiding collisions        with PSS/SSS)    -   Alt 3: Do nothing about PSS/SSS DM-RS collisions in Rel-11        -   3a: Puncture DM-RS        -   3b: Forbid PDSCH transmissions in PRBs with PSS/SSS

For Alt 1/Alt 2, a new signal design is needed, and it needs to beverified whether the new signaling could fulfill the requirement needs.Alt 3 seems most in-line with Rel-10 design, and Alt 3b would result inunused resources.

In 3GPP TS 36.213 V11.1.0, EPDCCH was introduced to improve the spectralefficiency and also the capacity of control channel. For a PhysicalDownlink Control Channel (PDCCH), there was a fix set of aggregationlevel {1,2,4,8}/blind decoding attempt split{6,6,2,2}. However, as thecoverage of EPDCCH is expected to be smaller than PDCCH and in order toalso efficiently utilize the blind decoding attempts, the aggregationlevel and blind decoding attempt distribution would depend on severalattributes such as the number of available resource elements for EPDCCHand the payload size of EPDCCH. As disclosed in 3GPP TS 36.211 V.11.1.0,for example, the aggregation level set as follows (Note that as shownbelow different downlink control information (DCI) formats could be indifferent payload sizes and downlink bandwidth configuration (N_(RB)^(DL)) is also an attribute to compute payload size):

-   -   The enhanced physical downlink control channel (EPDCCH) carries        scheduling assignments. An enhanced physical downlink control        channel is transmitted using an aggregation of one or several        consecutive enhanced control channel elements (ECCEs) where each        ECCE consists of multiple enhanced resource element groups        (EREGs), defined in Section 6.2.4A. The number of ECCEs used for        one EPDCCH depends on the EPDCCH format as given by Table        6.8A.1-2 and the number of EREGs per ECCE is given by Table        6.8A.1-1. Both localized and distributed transmission is        supported.    -   An EPDCCH can use either localized or distributed transmission,        differing in the mapping of ECCEs to EREGs and PRB pairs.    -   A UE shall monitor multiple EPDCCHs as defined in 3GPP TS 36.213        V11.1.0. One or two sets of physical resource-block pairs which        a UE shall monitor for EPDCCH transmissions can be configured.        All EPDCCH candidates in EPDCCH set S_(m) use either only        localized or only distributed transmission as configured by        higher layers. Within EPDCCH set S_(m) in subframe i, the ECCEs        available for transmission of EPDCCHs are numbered from 0 to        N_(ECCE,m,i)−1 and ECCE number n corresponds to        -   EREGs numbered (n mod N_(RB) ^(ECCE))+jN_(RB) ^(ECCE) in PRB            index └n/N_(RB) ^(ECCE)┘ for localized mapping, and        -   EREGs numbered └n/N_(RB) ^(S) ^(m) ┘+jN_(RB) ^(ECCE) in PRB            indices (n+j max (1, N_(ECCE) ^(EREG)))mod N_(RB) ^(S) ^(m)            for distributed mapping,    -   where j=0, 1, . . . , N_(ECCE) ^(EREG)−1, N_(ECCE) ^(EREG) is        the number of EREGs per ECCE, and N_(RB) ^(ECCE)=16/N_(ECCE)        ^(EREG) the number of ECCEs per resource-block pair. The        physical resource-block pairs constituting EPDCCH set S_(m) are        in this paragraph assumed to be numbered in ascending order from        0 to N_(RB) ^(S) ^(m) −1.

TABLE 6.8A.1-1 Number of EREGs per ECCE, N_(ECCE) ^(EREG). Normal cyclicprefix Extended cyclic prefix Special Special Special Normal subframe,subframe, Normal subframe, sub- configuration configuration sub-configuration frame 3, 4, 8 1, 2, 6, 7, 9 frame 1, 2, 3, 5, 6 4 8

TABLE 6.8A.1-2 Supported EPDCCH formats. Number of ECCEs for one EPDCCH,N_(EPDCCH) ^(ECCE) Case 1 Case 2 EPDCCH Localized Distributed LocalizedDistributed format transmission transmission transmission transmission 02 2 1 1 1 4 4 2 2 2 8 8 4 4 3 16 16 8 8 4 — 32 — 16Case 1 in Table 6.8A.1-2 applies when

-   -   DCI formats 2, 2A, 2B, 2C or 2D is used and N_(RB) ^(DL)≧25, or    -   any DCI format when n_(EPDCCH)<104 and normal cyclic prefix is        used in normal subframes or special subframes with configuration        3, 4, 8.        Otherwise, case 2 is used. The quantity n_(EPDCCH) for a        particular UE is defined as the number of downlink resource        elements (k, l) in a physical resource-block pair configured for        possible EPDCCH transmission of EPDCCH set S₀ and fulfilling all        of the following criteria:    -   they are part of any one of the 16 EREGs in the physical        resource-block pair, and    -   they are assumed by the UE not to be used for cell-specific        reference signals or CSI reference signals as given by Section        7.1.9 of 3GPP TS 36.213 V11.1.0, and    -   the index l in the first slot in a subframe fulfils        l≧l_(EPDCCHStart) where l_(EPDCCHStart) is given by Section        9.1.4.1 of 3GPP TS 36.213 V11.1.0.

Similarly, the EPDCCH blind decoding attempt distribution would havesomething to do with the number of available resource elements forEPDCCH and the payload size of EPDCCH as discussed in 3GPP TS 36.213V11.1.0.

-   -   For Tables 9.1.4-1a, 9.1.4-1b, 9.1.4-2a, 9.1.4-2b, 9.1.4-3a,        9.1.4-3b, 9.1.4-4a, 9.4.4-4b, 9.1.4-5a, 9.1.4-5b        -   Case 1 applies            -   when DCI formats 2/2A/2B/2C/2D are monitored and N_(RB)                ^(DL)≧25, or            -   for normal subframes and normal downlink CP when DCI                formats 1A/1B/1D/1/2/2A/2B/2C/2D/0/4 are monitored, and                when n_(EPDCCH)<104 (n_(EPDCCH) defined in section                6.8A.1 of 3GPP TS 36.211 V11.1.0), or            -   for special subframes with special subframe                configuration 3, 4, 8 and normal downlink CP when DCI                formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored;        -   Case 2 applies            -   for normal subframes and extended downlink CP when DCI                formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored or,            -   for special subframes with special subframe                configuration 1,2,6,7,9 and normal downlink CP when DCI                formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored, or            -   for special subframes with special subframe                configuration 1,2,3,5,6 and extended downlink CP when                DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D/0/4 are monitored;        -   otherwise            -   Case 3 is applied.                N_(RB) ^(X) ^(p) (defined in section 6.8A.1 of 3GPP TS                36.211 V11.1.0) is the number of PRB-pairs constituting                EPDCCH-PRB-set p

TABLE 9.1.4-1a EPDCCH candidates monitored by a UE (One DistributedEPDCCH-PRB-set - Case 1, Case 2) Number of PDCCH candidates Number ofPDCCH candidates M_(p) ^((L)) for Case 1 M_(p) ^((L)) for Case 2 N_(RB)^(X) _(p) L = 2 L = 4 L = 8 L = 16 L = 32 L = 1 L = 2 L = 4 L = 8 L = 162 [4] [2] [1] [0] [0] [4] [2] [1] [0] [0] 4 [8] [4] [2] [1] [0] [8] [4][2] [1] [0] 8 [6] [4] [3] [2] [1] [6] [4] [3] [2] [1]

TABLE 9.1.4-1b EPDCCH candidates monitored by a UE (One DistributedEPDCCH-PRB-set - Case 3) Number of PDCCH candidates M_(p) ^((L)) forCase 3 N_(RB) ^(X) ^(p) L = 1 L = 2 L = 4 L = 8 L = 16 2 [8] [4] [2] [1][0] 4 [4] [5] [4] [2] [1] 8 [4] [4] [4] [2] [2]

TABLE 9.1.4-2a EPDCCH candidates monitored by a UE (One LocalisedEPDCCH-PRB-set - Case 1, Case 2) Number of PDCCH Number of PDCCHcandidates M_(p) ^((L)) for candidates M_(p) ^((L)) for Case 1 Case 2N_(RB) ^(X) _(p) L = 2 L = 4 L = 8 L = 16 L = 1 L = 2 L = 4 L = 8 2 [4][2] [1] [0] [4] [2] [1] [0] 4 [8] [4] [2] [1] [8] [4] [2] [1] 8 [6] [6][2] [2] [6] [6] [2] [2]

TABLE 9.1.4-2b EPDCCH candidates monitored by a UE (One LocalisedEPDCCH-PRB-set - Case 3) Number of PDCCH candidates M_(p) ^((L)) forCase 3 N_(RB) ^(X) ^(p) L = 1 L = 2 L = 4 L = 8 2 [8] [4] [2] [1] 4 [6][6] [2] [2] 8 [6] [6] [2] [2]

TABLE 9.1.4-3a EPDCCH candidates monitored by a UE (Two DistributedEPDCCH-PRB-sets - Case 1, Case 2) Number of PDCCH candidates Number ofPDCCH candidates [M_(p1) ^((L)), M_(p2) ^((L))] for Case 1 [M_(p1)^((L)), M_(p2) ^((L))] for Case 2 N_(RB) ^(Xp) ₁ N_(RB) ^(Xp) ₂ L = 2 L= 4 L = 8 L = 16 L = 32 L = 1 L = 2 L = 4 L = 8 L = 16 2 2 [4, 4] [2, 2][1, 1] [0, 0] [0, 0] [4, 4] [2, 2] [1, 1] [0, 0] [0, 0] 4 4 [3, 3] [3,3] [1, 1] [1, 1] [0, 0] [3, 3] [3, 3] [1, 1] [1, 1] [0, 0] 8 8 [3, 3][2, 2] [1, 1] [1, 1] [1, 1] [3, 3] [2, 2] [1, 1] [1, 1] [1, 1] 4 2 [5,3] [3, 2] [1, 1] [1, 0] [0, 0] [5, 3] [3, 2] [1, 1] [1, 0] [0, 0] 8 2[4, 2] [4, 2] [1, 1] [1, 0] [1, 0] [4, 2] [4, 2] [1, 1] [1, 0] [1, 0] 84 [3, 3] [2, 2] [2, 1] [1, 1] [1, 0] [3, 3] [2, 2] [2, 1] [1, 1] [1, 0]

TABLE 9.1.4-3b EPDCCH candidates monitored by a UE (Two DistributedEPDCCH-PRB-sets - Case 3) Number of PDCCH candidates [M_(p1) ^((L)),M_(p2) ^((L))] for Case 3 N_(RB) ^(Xp) ₁ N_(RB) ^(Xp) ₂ L = 1 L = 2 L =4 L = 8 L = 16 2 2 [2, 2] [3, 3] [2, 2] [1, 1] [0, 0] 4 4 [2, 2] [2, 2][2, 2] [1, 1] [1, 1] 8 8 [2, 2] [2, 2] [2, 2] [1, 1] [1, 1] 4 2 [3, 1][3, 2] [3, 1] [1, 1] [1, 0] 8 2 [3, 1] [4, 1] [3, 1] [1, 1] [1, 0] 8 4[2, 2] [2, 2] [2, 2] [1, 1] [1, 1]

TABLE 9.1.4-4a EPDCCH candidates monitored by a UE (Two LocalisedEPDCCH-PRB-sets - Case 1, Case 2) Number of PDCCH Number of PDCCHcandidates candidates [M_(p1) ^((L)), M_(p2) ^((L))] [M_(p1) ^((L)),M_(p2) ^((L))]for Case 1 for Case 2 N_(RB) ^(Xp) ₁ N_(RB) ^(Xp) ₂ L = 2L = 4 L = 8 L = 16 L = 1 L = 2 L = 4 L = 8 2 2 [4, 4] [2, 2] [1, 1] [0,0] [4, 4] [2, 2] [1, 1] [0, 0] 4 4 [3, 3] [3, 3] [1, 1] [1, 1] [3, 3][3, 3] [1, 1] [1, 1] 8 8 [3, 3] [3, 3] [1, 1] [1, 1] [3, 3] [3, 3] [1,1] [1, 1] 4 2 [4, 3] [4, 2] [1, 1] [1, 0] [4, 3] [4, 2] [1, 1] [1, 0] 82 [5, 2] [4, 2] [1, 1] [1, 0] [5, 2] [4, 2] [1, 1] [1, 0] 8 4 [3, 3] [3,3] [1, 1] [1, 1] [3, 3] [3, 3] [1, 1] [1, 1]

TABLE 9.1.4-4b EPDCCH candidates monitored by a UE (Two LocalisedEPDCCH-PRB-sets - Case 3) Number of PDCCH candidates [M_(p1) ^((L)),M_(p2) ^((L))] for Case 3 N_(RB) ^(Xp) ¹ N_(RB) ^(Xp) ² L = 2 L = 4 L =8 L = 16 2 2 [3, 3] [3, 3] [1, 1] [1, 1] 4 4 [3, 3] [3, 3] [1, 1] [1, 1]8 8 [3, 3] [3, 3] [1, 1] [1, 1] 4 2 [4, 2] [4, 2] [1, 1] [1, 1] 8 2 [4,2] [4, 2] [1, 1] [1, 1] 8 4 [3, 3] [3, 3] [1, 1] [1, 1]

TABLE 9.1.4-5a EPDCCH candidates monitored by a UE (One localisedEPDCCH-PRB-set and one distributed EPDCCH-PRB-set, - Case 1, Case 2; p₁is the identity of the localised EPDCCH-PRB-set, p₂ is the identity ofthe distributed EPDCCH-PRB-set) Number of PDCCH candidates Number ofPDCCH candidates [M_(p1) ^((L)), M_(p2) ^((L))] for Case 1 [M_(p1)^((L)), M_(p2) ^((L))] for Case 2 N_(RB) ^(Xp) ₁ N_(RB) ^(Xp) ₂ L = 2 L= 4 L = 8 L = 16 L = 32 L = 1 L = 2 L = 4 L = 8 L = 16 2 2 [4, 4] [2, 2][1, 1] [0, 0] [0, 0] [4, 4] [2, 2] [1, 1] [0, 0] [0, 0] 4 4 [4, 2] [4,3] [0, 2] [0, 1] [0, 0] [4, 2] [4, 3] [0, 2] [0, 1] [0, 0] 8 8 [4, 1][4, 2] [0, 2] [0, 2] [0, 1] [4, 1] [4, 2] [0, 2] [0, 2] [0, 1] 2 4 [4,3] [2, 4] [0, 2] [0, 1] [0, 0] [4, 3] [2, 4] [0, 2] [0, 1] [0, 0] 2 8[4, 1] [2, 2] [0, 4] [0, 2] [0, 1] [4, 1] [2, 2] [0, 4] [0, 2] [0, 1] 42 [5, 2] [4, 2] [1, 1] [1, 0] [0, 0] [5, 2] [4, 2] [1, 1] [1, 0] [0, 0]4 8 [4, 1] [4, 2] [0, 2] [0, 2] [0, 1] [4, 1] [4, 2] [0, 2] [0, 2] [0,1] 8 2 [5, 1] [4, 2] [2, 1] [1, 0] [0, 0] [5, 1] [4, 2] [2, 1] [1, 0][0, 0] 8 4 [6, 1] [4, 2] [0, 2] [0, 1] [0, 0] [6, 1] [4, 2] [0, 2] [0,1] [0, 0]

TABLE 9.1.4-5b EPDCCH candidates monitored by a UE (one distributedEPDCCH-PRB-set and one localised EPDCCH-PRB-set - Case 1, Case 3); p₁ isthe identity of the localised EPDCCH-PRB-set, p₂ is the identity of thedistributed EPDCCH-PRB-set) Number of PDCCH candidates [M_(p1) ^((L)),M_(p2) ^((L))] for Case 3 N_(RB) ^(Xp) ₁ N_(RB) ^(Xp) ₂ L = 1 L = 2 L =4 L = 8 L = 16 2 2 [4, 1] [4, 2] [2, 2] [0, 1] [0, 0] 4 4 [4, 1] [4, 1][2, 2] [0, 1] [0, 1] 8 8 [4, 1] [4, 1] [2, 2] [0, 1] [0, 1] 2 4 [4, 1][4, 1] [2, 2] [0, 1] [0, 1] 2 8 [4, 1] [4, 1] [2, 2] [0, 1] [0, 1] 4 2[4, 1] [4, 1] [2, 2] [1, 1] [0, 0] 4 8 [4, 1] [4, 1] [2, 2] [0, 1] [0,1] 8 2 [4, 1] [4, 1] [4, 1] [0, 1] [0, 0] 8 4 [4, 1] [4, 1] [2, 2] [0,1] [0, 1]

If DMRS and PSS/SSS can coexist in the same PRB pair (i.e., anyalternative other than Alt.3b is chosen), PDSCH demodulated with DMRSand ePDCCH can be scheduled in the PRB pairs containing PSS/SSS (e.g.,the central 6 PRB). However, the number of available resource elements(REs) would be different among the PRB pairs containing PSS/SSS and thePRB pairs not containing PSS/SSS given that PSS/SSS may occupy part ofthe downlink bandwidth. It is not clear how to determine the ePDCCHaggregation level set and blind decoding attempt split.

Various embodiments disclosed herein are directed to methods fordetermining the ePDCCH aggregation level set and blind decoding attemptsplit when the numbers of available REs between different PRB pairs aredifferent. For example, according to one embodiment, a restriction ismade so that at least within a subframe that the ePDCCH candidates comefrom the PRB pair(s) with the same number of available REs. Moreover,the number is used to determine ePDCCH aggregation level set and blinddecoding attempt split. Alternatively, another restriction is made suchthat the numbers of available REs correspond to the same ePDCCHaggregation level set and blind decoding attempt split. In anotherembodiment, the ePDCCH candidates come from the PRB pairs with differentnumbers of available REs and a specific rule is used to derive aparameter for determining the ePDCCH aggregation level set and blinddecoding attempt split. More specifically, ePDCCH can be received fromthe PRB pairs with different numbers of available REs.

In one embodiment, one or more PRB pair(s) containing PSS/SSS is allowedto receive PDSCH demodulated with DMRS while it is not allowed toreceive ePDCCH. In another embodiment, at least within a TTI containingPSS/SSS, a UE receives ePDCCH on either PRB pair(s) containing PSS/SSSor PRB pair(s) not containing PSS/SSS. More specifically, in oneexample, all PRBs configured for ePDCCH for the UE either containPSS/SSS or do not contain PSS/SSS. In another example, ePDCCH isreceived on the PRB pairs containing the signal or the PRB pairs notcontaining the signal based on which camp contains more PRB pairs thatare configured for ePDCCH. In still another example, PDCCH is receivedon the PRB pairs containing the signal or the PRB pairs not containingthe signal based on an indication.

Alternatively, in one embodiment, in at least one subframe, if there ismore than one number of available resource elements among PRBs pairs, anumber is chosen to be used to determine the ePDCCH aggregation levelset and blind decoding attempt split. For example, a larger number canbe chosen for determining the ePDCCH aggregation level set and blinddecoding attempt split. More specifically, the number of availableresource elements in the PRB pairs not containing PSS/SSS is used todetermine the ePDCCH aggregation level set and blind decoding attemptsplit. In another example, a smaller number is chosen for determiningthe ePDCCH aggregation level set and blind decoding attempt split. Morespecifically, the number of available resource elements in the PRB pairscontaining PSS/SSS is used to determine the ePDCCH aggregation level setand blind decoding attempt split. In yet another example, a number ischosen based on the number of available resource elements in majorityPRB pairs. In another embodiment, in at least one subframe, if there ismore than one number of available resource elements among PRBs pairs,the ePDCCH aggregation level set and blind decoding attempt splitassociated with a number of available resource elements is used, whereinthe number is chosen from the more than one number.

In another embodiment, in at least in a subframe, if there is more thanone number of available resource elements among PRBs pairs, a valuedetermines the ePDCCH aggregation level set and blind decoding attemptsplit, wherein the value is derived from the more than one number. Forexample, in one embodiment, the value is an average of the more than onenumber. More specifically, ePDCCH is received on PRB pairs withdifferent numbers of available resource elements.

Referring back to FIGS. 3 and 4, the device 300 includes a program code312 stored in memory 310. In one embodiment, the CPU 308 could executeprogram code 312 to execute one or more of the following: (i) have, inat least one subframe, more than one number of available resourceelements among Physical Resource Block (PRB) pairs in a cell, and (ii)to receive an Enhanced Physical Downlink Control Channel (ePDCCH) on anumber of PRB pairs, wherein the PRB pairs have the same number ofavailable resource elements.

In another embodiment, the CPU 308 could execute the program code 312 toexecute one or more of the following: (i) have, in at least onesubframe, more than one number of available resource elements amongPhysical Resource Block (PRB) pairs in a cell, and (ii) to use a rule todetermine the ePDCCH aggregation level set and blind decoding attemptsplit.

In addition, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

1. A method in a wireless communication system, the method comprising: having, in at least one subframe, numbers of available resource elements among different Physical Resource Blocks (PRBs) are different in a cell; and receiving an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same as the number of available resource elements.
 2. The method of claim 1, wherein the numbers of available resource elements are different due to the presence of a signal.
 3. The method of claim 1, further comprising: determining the ePDCCH aggregation level set and blind decoding attempt split based on the number of available resource elements with PRB pairs receiving ePDCCH.
 4. The method of claim 2, wherein ePDCCH cannot be received on the PRB pair containing the signal, and wherein Physical Downlink Control Channel (PDSCH) demodulated with a Demodulation Reference Signal (DMRS) can be received on the PRB pair containing the signal.
 5. The method of claim 2, wherein the ePDCCH is received on either PRB pairs containing the signal or the PRB pairs not containing the signal.
 6. The method of claim 5, wherein whether ePDCCH is received on PRB pairs containing the signal or the PRB pairs not containing the signal depends on which type of PRB pairs are the majority among the PRB pairs configured for ePDCCH.
 7. A method in a wireless communication system, the method comprising: having, in at least one subframe, more than one number of available resource elements among PRBs pairs in a cell; and using a value to determine the ePDCCH aggregation level set and blind decoding attempt split.
 8. The method of claim 7, the numbers of available resource elements are different due to the presence of a signal.
 9. The method of claim 7, ePDCCH is received on PRB pairs with different numbers of available resource elements.
 10. The method of claim 7, wherein the value is based on one of the more than one number.
 11. The method of claim 7, wherein the value is derived from the more than one number.
 12. The method of claim 8, wherein the signal is Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS).
 13. A communication device in a wireless communication system, the communication device comprising: a control circuit; a processor installed in the control circuit; a memory installed in the control circuit and operatively coupled to the processor; wherein the processor is configured to execute a program code stored in memory to: have in at least one subframe, numbers of available resource elements among Physical Resource Blocks (PRBs) in a cell are different; and receive an Enhanced Physical Downlink Control Channel (ePDCCH) on a number of PRB pairs, wherein the PRB pairs have the same as the number of available resource elements.
 14. The communication device of claim 13, wherein the number of available resource elements is different due to the presence of a signal.
 15. The communication device of claim 13, wherein the ePDCCH is received on either PRB pairs containing the signal or the PRB pairs not containing the signal.
 16. The communication device of claim 13, wherein the processor is configured to execute a program code stored in memory to determine the ePDCCH aggregation level set and blind decoding attempt split based on the number of available resource elements with PRB pairs receiving ePDCCH.
 17. The communication device of claim 15, wherein ePDCCH cannot be received on the PRB pair containing the signal, and wherein Physical Downlink Control Channel (PDSCH) demodulated with a Demodulation Reference Signal (DMRS) can be received on the PRB pair containing the signal.
 18. The communication device of claim 13, wherein the processor is configured to execute a program code stored in memory to provide an indication whether ePDCCH is received on the PRB pairs containing the signal or the PRB pairs not containing the signal.
 19. The communication device of claim 15, wherein whether ePDCCH is received on PRB pairs containing the signal or the PRB pairs not containing the signal depends on which type of PRB pairs is majority among the PRB pairs configured for ePDCCH. 